/Engine/Plugins/FX/Niagara/Source/NiagaraEditor/Public/ViewModels/NiagaraSystemViewModel.h
Gets editor specific data which can be stored per system. If this data hasn't been created the default version will be returned.
[UNiagaraSystemEditorData](API\Plugins\NiagaraEditor\UNiagaraSystemEditorData) & GetEditorData() const